3D endoscopic endonasal craniectomy for intestinal type adeno-carcinoma (ITAC) of the nasal cavity.

BACKGROUND: The aim of this study was to describe the potential advantages of the 3D endoscope-assisted craniectomy for tumor of the nasal cavity. METHODS: A 77-year-old man with a 6 month history of persistent progressive right nasal obstruction and iposmia is reported. Physical examination, including nasal endoscopy, revealed a large mass within the right nasal cavity. He had no associated symptoms such as visual complaints, paresthesia, and facial pain. He worked as a carpenter. Further imaging by CT and MRI revealed a large, expansive nasal-ethmoid lesion that almost completely occupies the right nasal cavity with partial extension posterior to the choana, extensive erosion of the ethmoid. Medially marks the nasal septum with deviation to the left. Laterally it marks the medial wall of the maxillary sinus and at the top it is in contact with the cribriform plate which seems to be interrupted in the right parasagittal seat at the 3rd anterior of the olfactory cleft. Histopathological analysis of the specimen was consistent with sinonasal adenocarcinoma, intestinal type (ITAC) cT4aN0 ([1]). RESULTS: Patient was taken up for surgery by transnasal 3D endoscopic approach for excision of tumor with repair of the skull base defect, using Karl Storz IMAGE1 S D3-Link™ and 4-mm TIPCAM®. The mass could be dissected free of the dura and the entire specimen was removed completely and sent for histopthological examination. We followed our 8 main surgical steps: 1) Tumor disassembling; 2) Nasal septum removal; 3) Centripetal bilateral ethmoidectomy and sphenoidotomy; 4) Draf III frontal sinusotomy 5) Anterior and posterior ethmoidal artery closure 6) Skull base removal; 7) Intracranial work; 8) Reconstruction time. A 4 × 2.3 cm skull base defect was repaired using triple layer of fascia lata (Intracranial intradural, intracranial extradural and extracranial) and was sealed using tissue glue (TisselR). Post-operative recovery was uneventful, pack were removed on 3rd postoperative day and patient was discharged on the 7th post-operative day. After 2 years of follow up, the patient is free of disease. CONCLUSION: We describe 3D endoscopic transnasal craniectomy for Intestinal Type Adeno-Carcinoma (ITAC) of the nasal cavity as a feasible technique for the surgical management of sino-nasal tumors ([2].) Our experience with this approach has been outstanding. We firmly believe that in the first three steps of the procedure the 3D endoscope is not necessary because it extends the surgical time and induce eyestrain of the main surgeon. Nevertheless, 3D endoscope gives the major advantage during the skull base removal and the intracranial work. It offers an optimal vision and better perception of depth with safe manipulation of the instruments avoiding injuries to healthy tissue ([3]). Furthermore, 3D images offer better understanding of the relationship between anatomical landmarks, helping the didactic learning curve of our residents.

Eagle Syndrome: 3D endoscope-assisted anterior tonsillar fossa approach to styloid process.

BACKGROUND: The aim of this study was to describe the potential advantages of the 3D endoscope-assisted anterior tonsillar fossa approach to elongated styloid process. METHODS: A 58 years-old woman was reported to our Department with one-year history of odynophagia, latero-cervical pain on the left side, and ipsilateral foreign body sensation. Pain was dull and intermittent in nature. The patient had visited different clinics, she had a physiatric and maxillo-facial evaluation with two dental extraction without any relief of the symptoms. On physical examination a hard-bony consistency area was palpated over left-sided tonsillar fossa, evocating severe pain. Three-dimensional computed tomography (CT) confirmed an anomalous length of the left styloid process and a diagnosis of Eagle's syndrome (ES) was made. After careful surgical and anesthesiology evaluation, we decided to proceed with the partial excision of the styloid process with a 3d endoscope-assisted transoral anterior tonsillar fossa approach (Reddy et al., 2020). RESULTS: The patient was relieved of her symptoms after the surgery and was discharged after 1 day. Postsurgical healing was uneventful, pharyngodynia was observed for the first 48 h and treated with anti-inflammatory medication. No early or late postoperative complications, including massive bleeding, neurovascular injury or infection, were encountered. At 1 year follow up visit the patient was still asymptomatic and the CT scan did not show any abnormalities. The 3D endoscope provided a high-quality magnification of the tonsillar fossa, which allow us to correctly identify the site of incision. Styloid process was identified through digital palpation. After sufficient dissection of the tip, the distal part of the elongated styloid process was osteotomised and retrieved with a curved instrument. Local hemostasis was achieved and wound was closed in layers. CONCLUSION: Some authors suggested novel surgical approach for ES like transoral robotic surgery (Rizzo-Riera et al., 2020 [2]). We present the 3D endoscope-assisted anterior tonsillar fossa approach as a feasible alternative for the surgical management of ES. Our experience with this approach has been outstanding, guaranteeing an optimal vision and depth of the surgical field with safe manipulation of the instruments which avoided injuries to healthy tissue. Furthermore, 3d endoscope was a great didactic tool. In our opinion is not necessary to remove all the styloid process, as other authors suggest (Lisan et al., 2019 [3]), but is sufficient a partial styloidectomy after cutting the stylohyoid ligament.

Operational effectiveness of three-dimensional flexible endoscopy: an ex vivo study using a new model.

BACKGROUND AND OBJECTIVES: Two-dimensional (2D) images lack depth information and thus provide probabilistic recognition that do not completely match the actual three-dimensional (3D) information. Here, we investigated the operability of 3D endoscopes. METHODS: A 3D operation model was developed by passing 20 silk threads through upper and lower plates at 2-mm intervals in front and back rows separated by 1 mm. We evaluated accuracy and time of operating an electrosurgical knife. A successful operation was defined as pulling only a front-row thread; an unsuccessful operation was defined as pulling no thread (miss) or simultaneously pulling front- and back-row threads. Endoscopists (four experts, six trainees) repeated the operation under 2D and 3D conditions until individually accumulating 10 successful attempts under each condition. RESULTS: Operation accuracy was significantly higher for 3D compared with 2D in all endoscopists (88.5% vs. 61.3%; p < 0.01) and in both experience groups (trainees: 84.5% vs. 61.2%; experts: 95.2% vs. 61.5%; both p < 0.01). Operation time was significantly shorter for 3D compared with 2D in all endoscopists (12.5 ± 4.1 s vs. 14.8 ± 4.7 s; p < 0.01) and in both experience groups (trainees: 12.8 ± 4.2 s vs. 15.2 ± 4.9 s; experts: 12.1 ± 4.0 s vs. 14.3 ± 4.3 s; both p < 0.01). DISCUSSION: Compared with 2D endoscopy, 3D endoscopy significantly improved operation accuracy and shortened operation time, suggesting that 3D endoscopy enables accurate operation by depth information, aiding spatial recognition.

Comparison of 3D endoscopy and conventional 2D endoscopy in gastric endoscopic submucosal dissection: an ex vivo animal study.

BACKGROUND AND OBJECTIVES: Conventional endoscopy provides two-dimensional (2D) information without depth information. This study compared three-dimensional (3D) endoscopy and 2D endoscopy using an endoscopic submucosal dissection (ESD) training model to evaluate the utility of 3D endoscopy. METHODS: Porcine stomach specimens (7 × 7 cm) were prepared from commercially available resected porcine stomachs and a 10-mm hypothetical lesion was marked at the center of each specimen. Specimens were individually placed in an ESD training model, and subjected to either 2D or 3D ESD. En bloc resection rate, perforation rate, incision time, dissection time, and levels of five eyestrain symptoms (fatigue, pain, blurred vision, head-heaviness, and headache; 100-mm visual analog scale) were compared between the 2D and 3D procedures. In a crossover design, 8 endoscopists each performed two 2D and two 3D procedures. RESULTS: All 32 lesions were resected en block, but perforation occurred in one 2D procedure. Incision time was significantly shorter in 3D ESD than in 2D ESD (102.8 ± 42.1 s vs. 135.8 ± 65.7 s, p < 0.05). Dissection time was also significantly shorter in 3D ESD than in 2D ESD (366.3 ± 187.6 s vs. 517.8 ± 282.3 s, p < 0.05). Differences in levels of all symptoms except blurred vision between before and after ESD were larger in 3D ESD than in 2D ESD. CONCLUSIONS: Incision time and dissection time were significantly shorter in 3D ESD compared with 2D ESD, but eyestrain was increased. Depth information from 3D images appears to facilitate rapid and stable ESD maneuvers.

Development of stereo endoscope system with its innovative master interface for continuous surgical operation.

BACKGROUND: Although robotic laparoscopic surgery has various benefits when compared with conventional open surgery and minimally invasive surgery, it also has issues to overcome and one of the issues is the discontinuous surgical flow that occurs whenever control is swapped between the endoscope system and the operating robot arm system. This can lead to problems such as collision between surgical instruments, injury to patients, and increased operation time. To achieve continuous surgical operation, a wireless controllable stereo endoscope system is proposed which enables the simultaneous control of the operating robot arm system and the endoscope system. METHODS: The proposed system consists of two improved novel master interfaces (iNMIs), a four-degrees of freedom (4-DOFs) endoscope control system (ECS), and a simple three-dimensional (3D) endoscope. In order to simultaneously control the proposed system and patient side manipulators of da Vinci research kit (dVRK), the iNMIs are installed to the master tool manipulators of dVRK system. The 4-DOFs ECS consists of four servo motors and employs a two-parallel link structure to provide translational and fulcrum point motion to the simple 3D endoscope. The images acquired by the endoscope undergo stereo calibration and rectification to provide a clear 3D vision to the surgeon as available in clinically used da Vinci surgical robot systems. Tests designed to verify the accuracy, data transfer time, and power consumption of the iNMIs were performed. The workspace was calculated to estimate clinical applicability and a modified peg transfer task was conducted with three novice volunteers. RESULTS: The iNMIs operated for 317 min and moved in accordance with the surgeon's desire with a mean latency of 5 ms. The workspace was calculated to be 20378.3 cm3, which exceeds the reference workspace of 549.5 cm3. The novice volunteers were able to successfully execute the modified peg transfer task designed to evaluate the proposed system's overall performance. CONCLUSIONS: The experimental results verify that the proposed 3D endoscope system enables continuous surgical flow. The workspace is suitable for the performance of numerous types of surgeries. Therefore, the proposed system is expected to provide much higher safety and efficacy for current surgical robot systems.

Three-dimensional endoscopic visualization in functional endoscopic sinus surgery.

Three-dimensional (3D) stereoscopic vision in sinus surgery has been achieved with the microscope so far. The introduction of two-dimensional (2D) endoscopes set a milestone in the visualization of the surgical field and paved the way to functional endoscopic sinus surgery (FESS), although the 2D endoscopes cannot provide a stereoscopic visualization. The latest technology of 3D endoscopes allows stereoscopic vision. We provide a clinical investigation of all commercially available 3D endoscopes in FESS to compare their clinical value and efficacy to routinely used conventional 2D HD endoscopes. In this prospective, randomized, controlled clinical study, 46 patients with polypoid chronic rhinosinusitis underwent FESS with one of the following three endoscopes: 2D 0° high definition (HD), 3D 0° standard definition (SD) and 3D 0° HD. Four surgeons qualitatively assessed endoscopes on stereoscopic depth perception (SDP) of the surgeon, sharpness and brightness of the image, as well as their comfort in use during surgery. Surgeons assessed the brightness of the control (2D HD) significantly better than 3D SD (p = 0.009) and brightness of 3D HD was rated significantly better than 3D SD (p = 0.038). Stereoscopic depth perception (SDP) of 3D SD was assessed highly significantly better than the control (2D HD) (p = 0.021), whereas 3D HD displayed best SDP (p = 0.0001). The comfort in use was rated significantly higher in the 3D HD group compared to the control group (p = 0.025). No significant differences in sharpness could be seen among all endoscopes. 3D HD endoscopy provides an improvement in SDP and brightness of the surgical field. It enhances the intraoperative visualization and is therefore an important and efficient development in endoscopic sinus surgery.

2D versus 3D Endoscopy: Head-to-Head Comparison in a Simulated Model of Endoscopic Endonasal Dural Suturing.

Objective Endonasal dural suturing (EDS) has been reported to decrease the incidence of cerebrospinal fluid fistula. This technique requires handling of single-shaft instrumentation in the narrow endonasal corridor. It has been proposed that three-dimensional (3D) endoscopes were associated with improved depth perception. In this study, we sought to perform a comparison of two-dimensional (2D) versus 3D endoscopy by assessing surgical proficiency in a simulated model of EDS. Materials and Methods Twenty-six participants subdivided into groups based on previous endoscopic experience were asked to pass barbed sutures through preset targets with either 2D (Storz Hopkins II) or 3D (Storz TIPCAM) endoscopes on 3D-printed simulation model. Surgical precision and procedural time were measured. All participants completed a Likert scale questionnaire. Results Novice, intermediate, and expert groups took 11.0, 8.7, and 5.7 minutes with 2D endoscopy and 10.9, 9.0, and 7.6 minutes with 3D endoscopy, respectively. The average deviation for novice, intermediate, and expert groups (mm) was 5.5, 4.4, and 4.3 with 2D and 6.6, 4.6, and 3.0 with 3D, respectively. No significant difference in procedural time or accuracy was found in 2D versus 3D endoscopy. 2D endoscopic visualization was preferred by the majority of expert/intermediate participants, while 3D endoscopic visualization by the novice group. Conclusion In this pilot study, there was no statistical difference in procedural time or accuracy when utilizing 2D versus 3D endoscopes. While it is possible that widespread familiarity with 2D endoscopic equipment has biased this study, preliminary analysis suggests that 3D endoscopy offers no definitive advantage over 2D endoscopy in this simulated model of EDS.

From Exoscope into the Next Generation.

An exoscope, high-definition video telescope operating monitor system to perform microsurgery has recently been proposed an alternative to the operating microscope. It enables surgeons to complete the operation assistance by visualizing magnified images on a display. The strong points of exoscope are the wide field of view and deep focus. It minimized the need for repositioning and refocusing during the procedure. On the other hand, limitation of magnifying object was an emphasizing weak point. The procedures are performed under 2D motion images with a visual perception through dynamic cue and stereoscopically viewing corresponding to the motion parallax. Nevertheless, stereopsis is required to improve hand and eye coordination for high precision works. Consequently novel 3D high-definition operating scopes with various mechanical designs have been developed according to recent high-tech innovations in a digital surgical technology. It will set the stage for the next generation in digital image based neurosurgery.

Quantitative Analysis of Velopharyngeal Movement by Applying Principal Component Analysis to Range Images Produced by a Three-Dimensional Endoscope.

Objectives: The purpose of this study was to develop a new technique for analyzing velopharyngeal movement and to investigate its utility. Materials and Methods: Velopharyngeal motion of 20 normal individuals was analyzed. A three-dimensional (3D) endoscope was inserted into the oral cavity, and the movement of the soft palate was measured using an exclusive fixation device. Range images of the soft palate were produced during phonation of the Japanese vowel /a/, and virtual grids were then overlaid on these images. Principal component analyses were applied to the 3D coordinates of the intersections of the virtual grids. The centers of gravity of the virtual grids were calculated, and the magnitude of the shift of the grid intersections during phonation was calculated. Results: The first and the second principal component scores were responsible for the upper posterior direction and the upper direction, respectively. The average magnitude of the shift of the center of gravity was 4.75 mm in males and 4.33 mm in females. Conclusions: Quantitative analysis of velopharyngeal movement was achieved by a method of applying principal component analysis (PCA) to the range images obtained from a 3D endoscope. There was no sex difference in velopharyngeal movement.

Three-Dimensional Versus Two-Dimensional Neuroendoscopy: A Preclinical Laboratory Study.

BACKGROUND: Use of traditional two-dimensional (2-D) neuroendoscopy is limited by lack of depth perception. The advent of next-generation three-dimensional (3-D) endoscopes potentially compensates for this limitation. The aim of this study was to objectively compare the 2 modalities in a controlled laboratory environment. METHODS: Using 2-D and 3-D endoscopes, 8 participants performed simple and complex motor tasks. Participants were divided into 3 groups: novice (n = 3), beginner (n = 4), and expert (n = 1), based on prior neuroendoscopy training. Efficiency of completing simple motor tasks in an allocated time and time to complete complex motor tasks were recorded for both visualization methods with demerits for inaccuracy. RESULTS: Inaccuracy was reduced with increasing experience in the use of the 3-D endoscope for simple motor tasks such as spiral drawing (P = 0.04), but there was no statistical difference in completion time for complex motor tasks pertaining to depth perception among the groups (P > 0.05) or within groups for simple or complex tasks. To assess the impact on the learning curve, we analyzed the performance improvement in use of the other endoscope based on which endoscope each participant used first. There was marked improvement in accuracy and efficiency of 2-D scope use in the "3-D first" group for performing simple motor tasks such as dotted-line drawing (P = 0.002), but no benefit was observed for complex motor tasks. CONCLUSIONS: Our data do not support the superiority of the 3-D endoscope over its conventional 2-D congener, although its use may shorten the learning curve associated with neuroendoscopy, regardless of subjects' prior experience with neuroendoscopy.

A 3D endoscopic transtubular transcallosal approach to the third ventricle.

OBJECT: Surgical approaches to deep-seated brain pathologies, specifically lesions of the third ventricle, have always been a challenge for neurosurgeons. In certain cases, the transcallosal approach remains the most suitable option for targeting lesions of the third ventricle, although retraction of the fornices and wall of the third ventricle have been associated with neuropsychological and hypothalamic deficits. The authors investigated the feasibility of an interhemispheric 3D endoscopic transcallosal approach through a minimally invasive tubular retractor system for the management of third ventricular lesions. METHODS: Three-dimensional endoscopic transtubular transcallosal approaches were performed on 5 preserved cadaveric heads (10 sides). A parasagittal bur hole was placed using neuronavigation, and a tubular retractor was inserted under direct endoscopic visualization. Following observation of the vascular structures, fenestration of the corpus callosum was performed and the retractor was advanced through the opening. Transforaminal, interforniceal, and transchoroidal modifications were all performed and evaluated by 3 surgeons. RESULTS: This approach provided enhanced visualization of the third ventricle and more stable retraction of corpus callosum and fornices. Bayonetted instruments were used through the retractor without difficulty, and the retractor applied rigid, constant, and equally distributed pressure on the corpus callosum. CONCLUSIONS: A transtubular approach to the third ventricle is feasible and facilitates blunt dissection of the corpus callosum that may minimize retraction injury. This technique also provides an added degree of safety by limiting the free range of instrumental movement. The combination of 3D endoscopic visualization with a clear plastic retractor facilitates safe and direct monitoring of the surgical corridor.

Range image of the velopharynx produced using a 3-D endoscope with pattern projection.

OBJECTIVES/HYPOTHESIS: To measure movements of the velopharynx in detail, a novel method of producing range images of the velopharynx was developed using a 3-D endoscope. The purpose of this paper is to introduce this system and to clarify its accuracy. STUDY DESIGN: The standard errors of repeated measurements, intraclass correlation coefficients (ICC), ICC(1,1) for intrarater reliability, and ICC(2,1) for interrater reliability were measured using a phantom of the nasopharynx. METHODS: An endoscopic measuring system was developed in which a pattern projection system was incorporated into a commercially available 3-D endoscope. Right and left images of the endoscope were integrated into one video file and digitized at a horizontal and vertical resolution of 640 × 480 pixels, as odd and even scanning lines, respectively. After separation of the video file into right and left images by interlace interpolation, correcting the distortion of the camera images, rectifying, and stereo-matching range images of the velopharynx were produced. The distances between two points, which were marked at an interval of 5 mm on the uvula and the pharynx of the phantom, were measured. RESULTS: The standard errors of repeated measurements were 0.02 horizontally and 0.01 vertically. The ICC(1,1) and ICC(2,1) were 0.83 and 0.94, and both correlation coefficients were considered to be "almost perfect." CONCLUSION: The present endoscopic measuring system provided relatively accurate and reliable range images of the velopharynx, and enabled quantitative analysis of movements of the velopharynx.

From Exoscope into the Next Generation

An exoscope, high-definition video telescope operating monitor system to perform microsurgery has recently been proposed an alternative to the operating microscope. It enables surgeons to complete the operation assistance by visualizing magnified images on a display. The strong points of exoscope are the wide field of view and deep focus. It minimized the need for repositioning and refocusing during the procedure. On the other hand, limitation of magnifying object was an emphasizing weak point. The procedures are performed under 2D motion images with a visual perception through dynamic cue and stereoscopically viewing corresponding to the motion parallax. Nevertheless, stereopsis is required to improve hand and eye coordination for high precision works. Consequently novel 3D high-definition operating scopes with various mechanical designs have been developed according to recent high-tech innovations in a digital surgical technology. It will set the stage for the next generation in digital image based neurosurgery.